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Öğe Assessment of antioxidant system and enzyme/nonenzyme regulation related to ascorbate-glutathione cycle in ferulic acid-treated Triticum aestivum L. roots under boron toxicity(TUBITAK SCIENTIFIC & TECHNICAL RESEARCH COUNCIL TURKEY, 2020) Konakçı, Ceyda Özfidan; Yıldıztugay, Evren; Elbasan, Fevzi; Yıldıztugay, Ayşegül; Küçüködük, MustafaFerulic acid (FA; 3-methoxy-4-hydroxycinnamic acid) can eliminate stress-induced damage because of its ability to induce antioxidant activity under stress. The aim of this study was to identify the effects of FA on water status, antioxidant system, and lipid peroxidation in wheat (Triticum aestivum L.) roots exposed to boron (B) stress. Plants were grown in hydroponic culture containing the combination or alone form of 25-75 mu M FA and 4-8 mM B. Stress significantly decreased growth (RGR), water content (RWC), proline content (Pro), and osmotic potential (psi(H)). However, FA alleviated the decrease in RGR, RWC, and Pro content. Compared to the control groups, stress decreased the activities of superoxide dismutase (SOD), peroxidase (POX), catalase, and ascorbate peroxidase (APX), but an increase was only observed in glutathione reductase (GR) activity. Hydrogen peroxide (H2O2) content accumulated with B stress. Besides, a notable decrease was observed in the scavenging activity of hydroxyl radical (OH center dot); thus, wheat roots had high lipid peroxidation (thiobarbituric acid reactive substance content). In response to stress, FA triggered the activities of SOD, POX, and APX. Moreover, when FA was made present in stressed wheat roots, we observed the enhanced activities of dehydroascorbate reductase, and monodehydroascorbate reductase and dehydroascorbate contents which are related to ascorbate-glutathione cycle, so FA could maintain ascorbate (AsA) regeneration. However, when wheat roots were treated with stress, FA did not induce the regeneration of glutathione because of decline in GR activity. Due to successful elimination of H2O2 content, the exogenous application of FA alleviated B-induced lipid peroxidation in wheat. Consequently, FA eliminated the damage induced by B stress via the increased POX and the enzymes related to Asada-Halliwell pathway (AsA-GSH cycle) in wheat roots.Öğe Çoklu streslere maruz bırakılan çeltik (Oryza sativa L.) yapraklarında eksojen skandiyum (sc)'un reaktif oksijen türleri (ROS) ve antioksidan savunma sistemi üzerine etkileri(Selçuk Üniversitesi Fen Bilimleri Enstitüsü, 2019) Elbasan, Fevzi; Yıldıztugay, EvrenTuz ve/veya kuraklık stresleri bitkide, sodyum (Na+) klorür (Cl-) alımını, bitki büyüme ve gelişimini olumsuz yönde etkileyen ve bunların sonucunda reaktif oksijen türlerinin (ROS) oluşmasına neden olan en önemli stres faktörleri arasındadır. Bunlara bağlı olarak kloroplastlarda süperoksit anyon radikali (O2•-), hidrojen peroksit (H2O2) ve hidroksil radikali (OH•) gibi ROS üretiminde artışa neden olmaktadır. Bu çalışmanın amacı, tuz (100 mM) ve/veya kuraklık (PEG %5) altındaki çeltik (Oryza sativa L.) fidelerindeki fotosentetik, biyokimyasal ve fizyolojik parametreler üzerine nadir toprak elementlerinden (NTE) olan skandiyum'un (Sc) (25-50 mikromolar) etkilerinin değerlendirmektir. Sonuçlar, stres koşulları altında büyüme (RGR), bağıl su içeriği (RWC), ozmotik potansiyel ve fotosentetik verimde (Fv/Fm) önemli azalmalara neden olduğunu göstermiştir. Stres koşullarında prolin içeriklerinde önemli değişimler olmamasına rağmen, kombine stres uygulaması dışındaki Sc (25 mikromolar) uygulamasında prolin içeriklerinde artış olmuştur. Tuz ve/veya kuraklık stresleri altındaki çeltik fidelerinde süperoksit dismutaz (SOD) katalaz (CAT) peroksidaz (POX) ve glutatyon redüktaz (GR) aktivitelerinde azalmalar görülmüştür. Bunlardan dolayı tuz ve/veya kuraklık stresiyle hidrojen peroksit (H2O2) ve lipid peroksidasyonu (TBARS miktarı) artış gözlemlenmiştir. Glutatyon-S-transferaz (GST) ve NADPH oksidaz (NOX) aktivitelerinde önemli değişimler görülmemiştir. Stresle birlikte Sc uygulamaları antioksidan enzim aktivitelerini indüklemiştir. Sonuç olarak, Sc ve stres faktörleri çeltik bitkisinde stresle artan oksidatif hasarın etkilerini iyileştirmiştir.Öğe Hydrogen sulfide (H2S) and nitric oxide (NO) alleviate cobalt toxicity in wheat (Triticum aestivum L.) by modulating photosynthesis, chloroplastic redox and antioxidant capacity(Elsevier B.V., 2020) Özfidan Konakçı, Ceyda; Yıldıztugay, Evren; Elbasan, Fevzi; Küçükoduk, Mustafa; Türkan, İsmailThe role of hydrogen sulfide (H2S)/nitric oxide (NO) in mitigating stress-induced damages has gained interest in the past few years. However, the protective mechanism H2S and/or NO has towards the chloroplast system through the regulation of redox status and activation of antioxidant capacity in cobalt-treated wheat remain largely unanswered. Triticum aestivum L. cv. Ekiz was treated with alone/in combination of a H2S donor (sodium hydrosulfide (NaHS,600?M)), a NO donor (sodium nitroprusside (SNP,100?M)) and a NO scavenger (rutin hydrate (RTN,50?M)) to assess how the donors affect growth, water relations, redox and antioxidant capacity in chloroplasts, under cobalt (Co) concentrations of 150-300 ?M. Stress decreased a number of parameters (growth, water content (RWC), osmotic potential (??), carbon assimilation rate, stomatal conductance, intercellular CO2 concentrations, transpiration rate and the transcript levels of rubisco, which subsequently disrupt the photosynthetic capacity). However, SNP/NaHS counteracted the negative effects of stress on these aforementioned parameters and RTN application with stress/non-stress was reversed these effects. Hydrogen peroxide (H2O2) and TBARS were induced under stress in spite of activated ascorbate peroxidase (APX). SNP/NaHS under stress increased activation of superoxide dismutase (SOD), peroxidase (POX), APX, glutathione reductase (GR), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), ascorbate (tAsA) and glutathione (GSH). In conclusion, NaHS/SNP are involved in the regulation and modification of growth, water content, rubisco activity and up-regulation of ascorbate-glutathione cycle (AsA-GSH) in chloroplast under stress. © 2020 Elsevier B.V.